Why fonts look the way they do and how to classify different typefaces

Imaginary lines

The baseline is the imaginary horizontal line where all of the characters in a font sit. Characters don't necessarily site exactly on the baseline. Characters such as an x is more likely to sit on the baseline, where a character like the o may sit slightly below it. The capline is the horizontal line where the capital letters of a font reach to. The meanline is the imaginary horizontal line across lowercase characters.

Different characters oftentimes violate all the imaginary lines so it's difficult to tell exactly where these lines are.

Distances

The cap height is the distance between the baseline and the capline

The x-height is the distance between the baseline and the meanline. It's also usually the height of the lowercase x because the x has very square top and bottoms that easily identify the height of this line (versus a letter like the lowercase o which sometimes defies the meanline and baseline by going above below them. The x-height can vary widely among different typefaces.

Point Size is the distance between the descender line and the cap height. Curiously, the ratio between in x-height/ascenders and descenders can dramatically affect the point size. Therefore typeface of similar point sizes can vary widely in size.

Physiological characteristics

Ascenders are the strokes above the x height in some lowercase letters such as t,l and h. Descenders are the strokes below the baseline on some lowercase letters such as the y,p and q. Stress is the degree of slant with which the counter of a letter is designed.

A Serif is a short cross stroke that projects from the main stroke. Serifs originated with Roman stonecutters, who finished off their rough edges with a tool that left a horizontal line. A typeface that lacks serifs is said to be sans-serif. Before the 1800s, all typefaces had serifs.

Counters are the hollow spaces in letters that make up the integral part of a letter. Generally speaking this refers only to letters which are closed like an o or an e. Sometimes, it referrers to even letter which are open like a "u".

Typeface Classifications

A font is the complete collection of all characters in a single variation and in a single size. Helvetica 12 pt condensed would be considered one font. This term is often misused in desktop publishing A type family is a series of variations of a typeface brought together because of their similarities. There are many ways of classifying typeface families into groups. Here are some of the groups you might encounter:

Bitmapped

Fonts that have been made to look like their resolution is low. This is done to emulate a computer display look. This style is en-vogue in current web design.

Blackletter (Old English)

Old style letterforms made to emulate an old English era.

Condensed

Fonts which are by their very nature tall and thin. Not to be confused with condensed versions of typefaces

Dingbats

Fonts which are really clipart. In the old days before clipart was so ubiquitous, typographers would design whole series of clipart embedded into fonts.

Display

This is a catch-all classification for fonts that don't fit one of the other profiles

Mono-spaced

Typewriter style fonts or fonts in which the letters have the same spacing.

San-Serif

Type without serifs. A lot of Swiss typefaces have this characteristic. Sans-serif type is heavily used on highways because without serifs the type is easier to read at large distances. Also used online because of increased readability.

Script

Fonts that emulate a handwriting style.

Serif

Letterforms with little feet or serifs at the end of some letters that helps the transition between characters.

Stressed

Type made to look like they have been photopied, mistreated or partially destroyed. Very popular a few years ago, but currently out of fashion.

Typeface Variations

A variation is a typeface based on an original design. Variations are made by changes in one of four ways: weight, proportion, angle or texture.

Weight Variation

A variation in the width of the strokes. extra-light, medium, bold, extra bold and heavy are some of the standard weight variations.

There is a difference between computer bolding and weight variations. Computers will sometimes add an outline of a certain width to the regular version of a font to fake a bold face. This closes the counters and makes type less readable. It's always optimal to use a bold variation rather than counting on the computer to create the bold face for you.

Proportion Variation

Variations in proportion refer to changes in the general dimensions of a typeface such as condensed, normal, expanded and wide.

Angle Variation

The types of angle variations are regular and italic. An italic version of a typeface is a slightly slanted version with specially designed variations of certain letters. An oblique version of a typeface can normally generated by taking the regular typeface and skewing it.